Created on:2021-07-17 10:29

Boiler hydraulic fault diagnosis and maintenance_ Fault analysis and treatment of coal mill

Boiler hydraulic fault diagnosis and maintenance_ Fault analysis and treatment of coal mill

① Abnormal hydraulic loading the reason for abnormal hydraulic loading is the poor oil quality of the hydraulic oil system. The poor oil quality is due to the poor quality of the compressed air used for sealing (including ash and water) and the failure to put the compressed air system into normal use. As a result, the filter screen is blocked, the solenoid valve is jammed, the hydraulic cylinder block is worn and the performance is reduced. The treatment methods are as follows: improve the quality of compressed air, use the hydraulic oil tank to seal the compressed air source normally, and reduce the ash in the oil tank; Install breathing valve of oil tank; Oil filling and changing should be strictly filtered; Clean the oil tank thoroughly; Regular sampling and testing of oil quality; The maintenance process of hydraulic parts is strictly required to make them free of dust; Change hydraulic loading to spring loading.

② The reasons for the feeding of the grinding roll are that the gap between the air ring of the grinding roll is too large, the sealing wind pressure is unstable, the seal (skeleton seal) on the grinding roll shaft is aging or improperly installed, etc. All of the above reasons can cause the roller bearing damage, which shows that the roller does not rotate and the coal mill drips a lot of raw coal. The treatment methods are as follows: installing the sealing air monitoring device on the sealing air pipe; The air ring gap of grinding roller should be strictly controlled within 0.5-0.8mm; Replace the aged framework seal in time to ensure the quality of framework seal.

③ When the pulverizer is in operation, a certain thickness of stone coal containing pulverized coal will be deposited in the inlet air duct. When the stone coal is heated by hot air, a part of the stone coal reaches the ignition point and burns. In serious cases, the pulverizer will be shut down and the hot air duct will be cracked. The reasons for this situation are as follows: the stone coal pipe is blocked by iron pieces, resulting in poor discharge, insufficient warm grinding time and too early coal feeding; Failure to inform the discharge personnel of the stone mill to operate in time when starting the mill; When the coal feeder is washed, the slime is thrown to the air inlet when the mill is started, blocking the stone coal discharge outlet. The solution is: reasonably adjust the gap between grinding roller and air ring to reduce the coal content of stone coal; When the coal feeder is blocked, try to avoid flushing with water, or handle the work order after flushing; An 80 mm high protective plate is installed at the air inlet to block the stone coal; When burning low calorific value coal, the emission of stone coal should be strengthened; In case of any abnormality, contact the operator to adjust the air inlet volume and the differential pressure of grinding bowl to reduce the generation of stone coal.

④ During the operation of pulverized coal pipe on fire, there were accidents of pulverized coal pipe on fire and burning out the pulverized coal pipe. The reason is that the resistance along the way from the four coal pipes at the outlet of the mill to the burner is different. Although the throttle orifice is considered to be used in the design, in the actual operation, the air pressure and wind speed of the four pulverized coal pipes are unbalanced. When the pulverized coal content is high, it is easy to cause the pulverized coal to pile up in the pulverized coal pipe. In addition, the inlet air temperature of the pulverizer is too high, and the volatile powder escapes, causing ignition. The way to solve the ignition problem of pulverized coal pipe is: Test and measure the air pressure and wind speed of four pulverized coal pipes, check the wear condition of throttle orifice plate, if the wear is too large, replace it in time; Strictly control the inlet air temperature not more than 80 ℃; In case of fire, close the hot air valve immediately, increase the cold air volume, stop coal feeding and organize fire fighting.

⑤ Other fault motor and coal mill coupling bolt fracture due to shear, the reason is the tooth coupling alignment accuracy is not enough, bolt fatigue. The accuracy of alignment should be improved to make the radial and axial jump less than 0.05mm; Replace the fatigue bolts regularly.

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